Water. It is fundamental for the survival of trees. It is absorbed by the roots from the soil and transported to the leaves. Water is essential for photosynthesis. This is the process by which trees convert sunlight, water, and carbon dioxide into glucose and oxygen. Additionally, water keeps the tree cool and ensures that nutrients can move throughout the tree. Without adequate water, a tree cannot grow, flower, or produce oxygen, which is the cornerstone of life on Earth.
Trees and Drought
Drought stress occurs when trees experience a shortage of water. This leads to various physiological changes that negatively impact their health and growth. Trees close their stomata to minimise water loss, which reduces photosynthesis and slows growth. Prolonged drought stress can lead to wilting, leaf loss, and ultimately the death of the tree. This stress also makes trees more vulnerable to diseases and pests. According to research published in Frontiers (2022), drought stress can severely disrupt water transport mechanisms in trees, reducing their chances of survival. Therefore, it is crucial to provide trees with adequate water.
Trees in Dry Conditions
Overwatering
Overwatering is a commonly underestimated problem for trees but can be as harmful as drought stress. When trees receive too much water, their roots become waterlogged and receive insufficient oxygen. This leads to root rot and reduced absorption of essential nutrients. It makes the tree susceptible to diseases and pests and impedes the tree’s growth. Overwatering can also affect the soil structure, worsening drainage and causing water to remain around the roots for longer periods. According to a study published in Tree Physiology (2008), prolonged saturated soil conditions can lead to hypoxia (oxygen deficiency) in the root zone. This oxygen deficiency arises because saturated soil impedes air exchange. In such cases, the tree does not receive enough oxygen, which is necessary for survival. Overwatering can severely affect the overall health and viability of the tree.
The Right Amount of Water
The right amount of water for a tree depends greatly on the species, age, soil type, and climatic conditions. Generally, young trees require more frequent watering to develop a deep root system, whereas mature trees need less frequent but more thorough watering. It is important to keep the soil moist but not saturated. Water should penetrate deeply into the soil to promote deep root growth. Regularly checking soil moisture can help strike the right balance. Soil moisture can be checked by digging a narrow hole next to the root ball or by sticking a probe into the root ball.
Better to Water Generously
It is better to give trees a substantial amount of water at once rather than a little bit at a time. Depending on the weather, a tree generally needs to be watered no more than once a week. During dry periods, it may be necessary to water twice a week to prevent dehydration. It is important that the soil dries out slightly between waterings. This encourages the roots to seek water on their own and to grow beyond the root ball. In wet conditions, watering once every two weeks may be sufficient, as the soil remains moist for longer.
A good amount of water at once is better than a little bit each time
Watering Trees in a Tree Box
Trees in a tree box or container require special care because their roots are confined to a limited space and soil. They need more frequent watering than trees planted in the ground because the soil in containers dries out faster. During dry weather, daily watering may be necessary, while in wet conditions, watering two to three times a week might be enough. It is important to keep the soil moist but not saturated and ensure that excess water can drain properly to prevent root rot.
Fruit trees generally need a lot of water
Tree Species and Water Needs
Tree species have different water needs depending on their natural habitat. Trees that require a lot of water, such as willows, alders, and poplars, often grow along waterways and in moist soils. These trees need regular and abundant watering to thrive. Additionally, fruit trees generally need more water. This is because fruit trees require water and energy not only for their growth but also for the production of flowers and fruits. During the flowering and fruiting season, the water needs of fruit trees are significantly higher to ensure the development of healthy and juicy fruits. It is important to keep the soil moist, especially during dry periods, to achieve a good harvest.
There are also tree species that are well-adapted to dry conditions and need little water, such as oaks, pines, and olive trees. These trees have deep roots that allow them to access water from deeper soil layers. This enables them to withstand long periods without rain.
Water reservoirs for watering young trees directly at the root ball
Watering Tools
Providing the right amount of water requires knowledge, time, and resources. Various tools are available to help manage watering and conserve water. For instance, a water reservoir, a plastic ring made from recycled material, helps provide water directly to the root zone of young trees. Water reservoirs ensure a concentrated water supply to the root zone where the tree needs it. The AquaBag, a water bag attached around the tree trunk, drips water over 6 to 10 hours. This allows the tree to absorb water efficiently at the roots. The TREEIB is a solution for large, monumental trees. This large water bag drips over 8 to 12 hours along the drip line of the canopy.
There are also solutions for supplying trees with water underground. For example, watering systems such as AquaMax are often used in public spaces. These irrigation tubes, with narrow openings, are installed around or beneath the root ball to supply water to the deeper tree roots. Above ground, the tube sticks out slightly, making it easy to provide water to the tree.
AquaBag, gradually empties around the base of the tree
Watering Trees
By paying attention to the right amount of water, trees can remain healthy and strong. It is important to consider factors such as the weather, the age of the tree, and whether the tree is planted in the ground or in a container. Regularly checking soil moisture helps prevent overwatering or underwatering. By approaching tree watering carefully, trees can grow optimally and contribute to a healthy and green environment.